Conveyor machine having pivot connector comprising curved track and rollers engaging track

ABSTRACT

A hitch apparatus is provided for use on a first mobile machine such as a conveyor vehicle to be used with a second mobile machine connected to the first machine. The apparatus includes a track member adapted for mounting at an end of the first machine, this member providing a track having two opposite sides and bent to form a circular arc having a center of curvature. A hitch unit is mounted for rolling movement on the track and can pivotably connect the end of the first machine to the second machine. The hitch unit includes rollers for engaging both of the opposite sides so that the track is captured between the rollers. The first machine is able to pivot about a substantially vertical axis extending through the center of curvature relative to the second machine and is connected to the second machine for movement therewith.

This application is a continuation of International application no.PCT/CA2008/000243 filed on Feb. 7, 2008, and claims priority of CanadianPatent Application No. 2,578,431 filed on Feb. 8, 2007.

This invention relates to conveyor systems and, in particular, mobileconveyor machines for use with endless conveyor belts and hitchingapparatus for use with such machines and other mobile machines.

Belt conveyors are well known and are efficient means for moving largequantities of materials such as ore, coal and granular stone over apredetermined distance extending either horizontally, vertically orboth. One form of conveyor system known for mining applications is asystem involving a series of conveyors mounted on wheels so as to makethe system easily movable. Because of the manner in which mines aredeveloped and extended, it may be necessary for a relatively longconveyor system to be moved along a substantially curved or zig zagcourse. Under such circumstances, it can be difficult and time consumingto move the conveyor system when required. It will also be appreciatedthat it may be necessary to move the conveyor system and to makeadjustments to the system fairly frequently as the mining machineadvances in a mine.

U.S. Pat. No. 5,366,059 issued Nov. 22, 1994 to Prairie Machine & PartsMfg. Ltd. describes and illustrates a conveyor system comprising aplurality of conveyor vehicles connected together in the form of a trainand also describes a steering system for steering this train ofvehicles. All but one of the vehicles in the train has a single pair ofsteerable wheels with the vehicle at the outby end of the train (that isthe end to which the mine material is being delivered) having twosteerable wheels. Hydraulic cylinders are used to steer each of thepairs of steerable wheels and there is a control mechanism forcontrolling and coordinating these cylinders in order to set thesteering angles of the pairs of wheels. In this known system, each pairof wheels is mounted on an axle and each pair is driven by an electrictram motor mounted along the longitudinal centre of the conveyorvehicle. One difficulty encountered with this known conveyor system isthat the system is relatively high along most of the length of the trainand therefore the ceiling of the region of the mine where the miningmachine is operating must be reasonably high, for example over six feet,to accommodate this conveyor system. Moreover, in this known system, theheight of each pair of wheels relative to the conveyor frame is notadjustable.

There is a need in the belt conveyor industry to provide a hitchingapparatus for pivotably connecting one end of a conveyor vehicle orconveyor machine to an adjacent end of another conveyor vehicle orconveyor machine. In particular, it is desirable to provide a newhitching apparatus which can be provided at one end of a conveyormachine that has a desirable low profile in order that the machine, aswell as other machines connected thereto, can be used in areas of minesor mine shafts that have a relatively low ceiling, for example, aceiling that is less than six feet. Such low ceiling mine areas and mineshafts are relatively common and it will be appreciated that often, froma mine economic standpoint, it may be too expensive to simply increasethe ceiling height in order to accommodate a mobile conveyor system.

In addition, there is a perceived need to provide a reliable hitchingapparatus for a mobile machine such as a mobile conveyor wherein thepivot point between two adjacent mobile machines or mobile conveyors islocated between the pair of wheels located adjacent one end of one ofthe machines in order to enable the conveyor machines to be steeredproperly using an automated steering system for the conveyor systemwhich is operated by an operator of the system.

According to one aspect of the invention, a hitching apparatus for useon a first mobile machine to be used with a second mobile machineconnected to the first mobile machine includes a track member adaptedfor mounting at an end of the first mobile machine. This track memberprovides a track having two opposite sides and is bent to form acircular arc having a center of curvature. The sides include an outerconvex side adapted to face towards the end of the first mobile machineand an inner concave side. The apparatus further includes a hitch unitmounted for rolling movement on the track and adapted to connectpivotably the end of the first mobile machine to the second mobilemachine. This hitch unit includes rollers for engaging both of theopposite sides whereby the track is captured by the rollers. The rollershave first and second sets of rollers having V-grooves formed abouttheir circumferences. The first set engages the outer convex side andthe second set engages the inner concave side. When the first mobilemachine has the hitching apparatus mounted thereon, this first machineis able to pivot about a substantially vertical axis extending throughthe center of curvature relative to the second mobile machine connectedthereto by the hitch apparatus.

In an exemplary embodiment of the hitching apparatus, the opposite sidesof the track are V-shaped and include an outer convex side adapted toface towards an adjacent end of the first mobile machine and an innerconcave side. In this exemplary version, the rollers includes first andsecond sets of rollers having V-grooves formed about theircircumferences, the first set engaging the outer convex side and thesecond set engaging the inner concave side.

According to a further aspect of the invention, a mobile conveyormachine for use with an endless conveyor belt and a conveyor system inthe form of a plurality of mobile conveyor machines pivotably connectedtogether in an end-to-end manner includes a conveyor mechanism having anelongate supporting frame with two longitudinal side frame members onopposite sides thereof and two opposite end sections between which theconveyor belt extends when mounted on the conveyor mechanism. A pair oftransversely aligned wheel units is provided to support and move theconveyor machine with each wheel unit having a wheel support structureconnected to a respective one of the side frame members and a wheelmounted on the wheel support structure for pivotable movement about arespective substantially vertical pivot axis for steering the conveyormachine. A curved track is mounted at one end of the supporting frameand extends in a substantially horizontal circular arc when the conveyormachine is positioned on a horizontal surface. The arc has a center ofcurvature located between the wheel units. A hitch unit is mounted onthe track for rolling movement along the track and is adapted to connectpivotably the conveyor machine at the one end to an adjacent end sectionof another mobile conveyor machine. There is also a sensor device fordetermining a substantially horizontal angle between a longitudinalcentral axis of the conveying machine and a central longitudinal axis ofanother mobile conveyor machine and for transmitting an electricalsignal indicative of this angle to a steering controller of the system.The conveyor machine during use as part of the conveyor system is ableto pivot about a substantially vertical axis extending through thecenter of curvature relative to another mobile conveyor machineconnected to the first mentioned conveyor machine by means of the hitchunit. In an exemplary embodiment, the hitch unit includes a car hitchframe and rollers each rotatably mounted in the hitch frame for rotationabout a substantially vertical axis and for rolling engagement with thetrack.

According to still another aspect of the invention, there is provided amobile conveyor machine for a cascading conveyor system in the form of aseries of mobile conveyor machines pivotably connected together in theform of a conveyor train. The conveyor machine comprises an elongatesupporting frame arranged substantially horizontally and havinglongitudinal side frame members and first and second ends. Thesupporting frame extends along a central longitudinal axis of theconveyor machine. A conveyor belt system is mounted on the supportingframe and arranged to convey materials from the first end to the secondend. A pair of transversely aligned propelling devices are eachseparately connected to the supporting frame for pivotable movementabout a generally vertical pivot axis this pair is located near butspaced from the first end and has a common axis of rotation when thepropelling devices are positioned to move the conveyor machine in astraightforward direction. The machine also includes a power mechanismfor steering the pair of propelling devices. A pivot mechanism forpivotably connecting the mobile conveyor machine at the first end to anend section of another mobile conveyor machine includes a curved trackbent in a horizontal circular arc having a center of curvature locatedmidway between the propelling devices on the axis of rotation andrigidly mounted on the supporting frame. The pivot mechanism furtherincludes a hitch unit mounted for rolling movement on the track andconnected to the track. This hitch unit has roller means engaging thetrack and is adapted for detachable connection to the another mobileconveyor machine.

These and other aspects of the disclosed mobile conveyor machine and ahitch apparatus for use on such a machine and other types of mobilemachines will become more readily apparent to those having ordinaryskill in the art from the following detail description taken inconjunction with the accompanying drawings.

In the drawings,

FIG. 1 is a top view of an exemplary embodiment of a mobile conveyormachine or vehicle constructed in accordance with the invention;

FIG. 2 is a side elevation of the conveyor vehicle of FIG. 1;

FIG. 3 is a bottom view of the conveyor machine of FIGS. 1 and 2;

FIG. 4 is a sectional elevation taken along the line IV-IV of FIG. 2;

FIG. 5 is a perspective view taken from above and from the tail pulleyend of the conveyor machine, this view showing an end section of themachine including its two wheels;

FIG. 6 is a sectional elevation taken along the line VI-VI of FIG. 1,this view showing details of the power steering arrangement for eachwheel;

FIG. 7 is a detail top view of a left hand wheel unit assembly of thevehicle of FIGS. 1 and 2, this view omitting the wheel itself for sakeof illustration;

FIG. 8 is a detail sectional elevation taken along the line VIII-VIII ofFIG. 7;

FIG. 9 is a detail end view of the wheel unit assembly of FIG. 7, thisview being taken from the left side of FIG. 7 and showing the wheelmounted on the assembly;

FIG. 10 is a detail sectional elevation taken along the line X-X of FIG.9;

FIG. 11 is a perspective detail view of a mounting plate weldment usedto support each wheel and its hydraulic motor;

FIG. 12 is a detail perspective view illustrating a pivotable motorsupport member mounted adjacent each wheel;

FIG. 13 is a vertical cross-section taken along the line XIII-XIII ofFIG. 15 illustrating how the rollers of the hitch unit engage the curvedtrack;

FIG. 14 is a detail view showing the transverse cross-section of thecurved track according to an exemplary embodiment;

FIG. 15 is a bottom view showing a portion of the curved track and thehitch unit mounted for rolling movement on the track;

FIG. 16 is a vertical cross-sectional detail taken along the lineXVI-XVI of FIG. 15;

FIG. 17 is a top view of a roller mounting support body which is part ofthe hitch unit;

FIG. 18 is a vertical cross-section of the roller mounting support bodytaken along the line XVIII-XVIII of FIG. 17;

FIG. 19 is a perspective view of the roller mounting support body ofFIG. 17 taken from above and from its pivot pin end;

FIG. 20 is perspective view of a pivoting hitch frame which is pivotablyconnected to the support body of FIG. 17, this hitch frame being shownfrom above and from an inner side thereof;

FIG. 21 is an inner side view of the hitch frame of FIG. 20;

FIG. 22 is a vertical cross-section of the hitch frame taken along theline XXII-XXII of FIG. 21;

FIG. 23 is a perspective view of an intercar angle sensor assemblymountable on the hitching apparatus;

FIG. 24 is a bottom view of the sensor assembly of FIG. 23;

FIG. 25 is an axial cross-section of the sensor assembly taken along theline XXV-XXV of FIG. 24;

FIG. 26 is a partial bottom view of the conveyor machine showing the endwhere the tail pulley is mounted and the hitching apparatus;

FIG. 27 is a detail plan view of the hitching apparatus mounted; on oneend of a mobile conveyor machine and showing an adjacent end section ofan adjacent conveyor machine connected thereto; and

FIG. 28 is a vertical cross-section taken along the line XXVIII-XXVIIIof FIG. 27 showing one of the two pivot pin connections joining the twoconveyor machines.

Major components of a conveyor vehicle constructed in accordance withthe invention are illustrated in FIGS. 1 to 5 of the drawings. Theillustrated, low profile conveyor vehicle 10 has been shown without theusual flexible conveyor belt, the location of which is only indicated inchain-link lines in FIG. 1 for sake of illustration. This conveyor belt12 is an endless conveyor belt and can be of standard constructiondepending upon the type of material being conveyed by the conveyorsystem. The illustrated exemplary vehicle is intended for use as anintermediate conveyor car of which there may be five, ten or more in atrain of conveyor vehicles similar to the train illustrated anddescribed in U.S. Pat. No. 5,366,059. It will be understood that inaddition to a plurality of intermediate conveyor vehicles pivotablyconnected end-to-end, there can also be a loading conveyor vehicle whichis located at the end of the train adjacent the mining machine, and adischarge conveyor vehicle located at the opposite end of the trainwhich is referred to as the outby end, that is, the end to which thetrain of vehicles delivers the material. The loading car assembly can beconstructed in a similar manner to the illustrated intermediate carassembly 10, except that it need not be provided with a hitch mechanismat its inby or hopper end, since there is no need to attach this end toanother conveyor vehicle. As for the discharge conveyor vehicle, it isprovided with two pairs of transversely aligned wheel units rather thana single pair of these wheel units described hereinafter. However, thewheel units on the discharge car can be constructed in the same manneras described hereinafter, including their steering mechanism and theirhydraulic drive mechanism. The discharge car is also provided with apivotable cross-conveyor for discharging the material onto a permanentor fixed conveyor in the mine. A cross-conveyor and its use is describedand illustrated in U.S. Pat. No. 5,366,059. A detailed description ofthe discharge car and its cross-conveyor herein is deemed unnecessary asa cross-conveyor system is not considered an aspect of the inventionclaimed herein.

Turning now to the illustrated conveyor vehicle 10, this vehicle has aconveyor mechanism 14 that includes an elongate, substantiallyhorizontal frame 16 and a series of spaced apart conveyor roller devices18 mounted on the horizontal frame 16 and adapted to support rotatablyan upper run of the continuous conveyor belt 12 extending betweenopposite end sections of the vehicle. The roller devices 18 can be ofstandard construction available from conveyor parts suppliers. Eachillustrated roller device comprises three metal rollers 20 which arepivotably connected together in an end-to-end fashion by their centralshafts. The outer end of each outer roller is connected by a chain 22(see FIG. 5) to a vertical support post 24 mounted on a main,longitudinally extending frame member of the main frame 16. The heightof each pair of posts 24 varies as shown to gradually increase theheight of the roller devices. In addition to the cylindrical, rotatablemetal rollers 20, there can also be provided impact rollers 26 of knownconstruction positioned below a U-shaped hopper member 28. It will beunderstood that the impact roller helps to absorb the impact of materialdropping onto the conveyor belt at this location.

The conveyor mechanism 14 further includes a tail pulley unit mountedadjacent one end of the conveyor mechanism on the horizontal frame 16and having a rotatable tail pulley indicated at 32. Further details ofthe construction of the tail pulley unit are provided hereinafter withreference to FIGS. 5 and 26. The conveyor mechanism 14 further includesa head pulley unit 34 mounted adjacent the second end of the conveyormechanism opposite the first end where the tail pulley is located. Thehead pulley unit includes a rotatable head pulley 36 which, in a knownmanner, can be provided with a gripping cylindrical surface whichenables the head pulley unit to drive the conveyor belt 12. There isalso an electric motor mechanism 38 which can be considered part of thehead pulley unit since it rotates the head pulley 36 to move theconveyor belt and thus to transport material from the tail pulley to thehead pulley. A belt scraper 40 of known construction can be mountedadjacent to the head pulley to help keep the conveying surface of thebelt clean. Mounted adjacent to the head pulley at the outby end of thevehicle is a material hopper 42 which helps direct the material onto theconveyor belt of the next conveyor vehicle of the train. In order toprovide a conveyor vehicle 10 having a low profile, there is provided apivoting hitch mechanism 44 at the inby end of the vehicle. This hitchmechanism includes a curved steel track and a rolling hitch device 48having two sets of grooved rollers located at 50 and 52 on two oppositeV-shaped sides of the track 46. Two car hitch pins 54 are located onopposite sides of the hitch device 48 which is able to pivot about acentral longitudinal axis of the vehicle by mean of central pivot pin 56(see FIG. 13). Located near the opposite head pulley end of the car aretwo hitch pin holders 60, one on each side of the frame 16.

The conveyor vehicle 10 has a pair of transversely aligned wheel unitsindicated generally at 62 for supporting and moving the conveyorvehicle. Each of these wheel units is separately connected to thehorizontal frame 16 including any extension thereof. In particular, eachwheel unit is connected to a respective longitudinally extending side ofthe frame. Each wheel unit has its own solid wheel, with the wheel onthe left side indicated at 64 and the wheel on the right hand sideindicated at 66. As explained more fully hereinafter, each wheel 64, 66is mounted for pivotable movement about a substantially vertical pivotaxis for steering purposes, that is, to steer the vehicle 10. In anexemplary embodiment of the conveyor vehicle, each wheel unit includes astandard hydraulic motor 68 shown clearly in FIG. 8. This motor is usedto rotate or drive the wheel of the respective wheel unit. Also, eachwheel unit includes a non-rotating wheel support structure indicatedgenerally at 70 for detachably connecting the wheel unit to thehorizontal frame, including any extension of this frame. The left handwheel unit 62, with its wheel removed, is illustrated in FIG. 7 and isillustrated with its wheel in FIGS. 8 and 9. FIG. 7 also shows a powersteering mechanism or power steering means 72 for steering the wheel ofthis wheel unit. The illustrated power steering mechanism includes ahydraulic linear actuator having a hydraulic cylinder 74 and an actuatorrod 76 slidable in the cylinder. A steering arm 77 having a L-shape isrigidly attached at one end to an upper section of a motor supportmember 144 (see FIG. 12) and is pivotably connected at its other end tothe rod 76 by means of a bolt and nut 80 (see FIG. 9). The closed end ofcylinder 74 is pivotably mounted by means of lugs 82 to an end of ahorizontally extending, elongate arm section 84 which is part of a wheelunit mounting plate 86. A nut and bolt combination 88 pivotably connectsa short connecting plate 90 that is rigidly attached to the end of thecylinder to the lugs 82. The actuator rod 76 can be provided with aspherical bearing 92 that is connected by threads to the outer end ofthe rod. This bearing is connected to the steering arm 77 by the nut andbolt 80.

In addition to the arm section 84, the flat mounting plate 86 includes amain plate portion 96 shown in FIG. 6. This main plate portion has agenerally rectangular shape except for cut-off bottom corners 98. Thearm section 84 extends horizontally from an upper corner of the mainplate portion 96. An advantage provided by the arm section 84 is thatthe hydraulic cylinder can then be pivotably mounted to the samemounting plate 86 as the wheel and its hydraulic motor 68. As can beseen from FIGS. 6 and 11, each wheel unit 62 and, in particular itsmounting plate 86 (which is part of the wheel support structure), isformed with a plurality of apertures or holes indicated generally byreference 100 which are provided to receive fasteners, preferably bolts,used to attach the respective wheel unit to the frame 16, including anyextension thereof. A plurality of fasteners 102 for this purpose areinsertable through spaced-apart apertures 104, four of which can be seenin FIG. 6. There are a plurality of the apertures 104 formed in eachlongitudinally extending side of the frame 16 and optionally additionalapertures can be provided in extension plates attachable to the mainframe members. The apertures 100 formed in the mounting plate 86 arelocated in opposite end sections of the mounting plate as clearly shownin FIG. 11. The illustrated aperture arrangement permits the height ofeach wheel unit relative to the horizontal frame 16 to be adjustedbetween either one of two possible positions, but it will be appreciatedby those skilled in the art that by providing further apertures 104, forexample, on each longitudinal frame member or an extension plate, it ispossible to provide for more than two possible height positions for eachwheel unit. In the position of the wheel unit illustrated in FIG. 6, thewheel unit 62 is at its maximum height relative to the frame 16. In thisposition, the overall height of the conveyor vehicle will be a minimumheight which, in an exemplary embodiment, is only four feet orforty-eight inches as compared to earlier conveyor vehicles such asthose described and illustrated in U.S. Pat. No. 5,366,059 which had anoverall height of six feet or seventy-two inches. In this position ofthe wheel units in the exemplary embodiment, the ground clearanceprovided under the vehicle is six inches. However, in the event thatmining conditions require greater ground clearance and provided the minearea has an adequate ceiling or working height for the conveyor system,the wheel units can be moved to the second position which can provide anadditional four inches of ground clearance for a total of ten inches. Inthis case, the overall height of the conveyor vehicle is fifty-twoinches.

Turning now to the wheel support structure 70, shown in FIGS. 8 and 11,the wheel support structure includes upper and lower, horizontallyextending wheel supporting arms 120, 122, both with rounded distal ends.The upper arm 120 can be formed from a single steel plate welded to thetop of mounting plate 86 and is formed with a round hole 122 to receivean upper pivot pin member. As illustrated, the lower support arm 122 canbe constructed of two short plate members 124, 126 which are weldedtogether at 128 and which extend at an obtuse angle to one another asshown in FIG. 8. The strength and rigidity of the connection between thesloping plate 124 and plate 86 can be strengthened by two verticallyextending gussets 130 which are welded to these plates. A top pivot pin132 is mounted in the hole 122 and is connected to the upper arm 120 bysix screws 134. The pivot pin can be provided with a central passageway(not shown) that extends downwardly from grease zerk 136. There is alsoa bottom pivot pin 138 having a reduced top end extending into acircular recess 140 formed in the rounded end section of the lowersupport arm 122.

In order to pivotably support the wheel and its hydraulic motor 68,there is provided a substantially annular motor support member 144 shownin FIG. 12. This support member has a circular recess 146 formed on itstop side and into this recess a reduced bottom end section of the toppivot pin 132 extends. Mounted in this recess is a spherical angularcontact bearing 148 which, in one embodiment, has a bore measuring 1¾″and has an outside diameter of 2 13/16 inch. Protecting this bearing andextending around the top edge of the bearing is a suitable seal such asa Chesterton Super Wiper seal 150. Similarly, extending around a reducedupper portion of the bottom pivot pin is a spherical angular contactbearing 152 which is sealed by means of a Chesterton super wiper seal154. The bottom pivot pin can be greased through grease zerk 156.

Returning to FIG. 12, it will be seen that the motor support member 144has a bottom extension 160 which is welded to the annular portion of thesupport member 144 and which has a circular hole 162. The bottom pivotpin projects through the hole 162 from the bottom and is detachablyconnected to the extension 160 by six screws 164 which extend through aflange extending around the bottom of this pivot pin. Formed between theextension 160 and the annular portion of support member 144 is a cavity166 which receives the rounded end portion of the horizontal plate 126.In this way, the support member 144 is pivotably supported from below.

It can also be seen from FIG. 12 that the support member 144 has aradially inwardly extending connecting flange 170, this flange beingformed with a series of fastener holes 172. As shown in FIG. 10, sixscrews 174 can be used to attach the hydraulic motor 68 to the flange170 along with its associated planetary gear box 176. The planetary gearbox has an annular rotating flange 178 which is attached by nine hexnuts 180 to a circular plate 182 forming a central portion of the hub ofthe wheel. The nuts are threaded onto studs 184 visible in FIG. 7, thesestuds extending through the rotating flange on the gear box. It isunderstood that the left and right wheels 64, 66 are solid rubber wheelsand, in one embodiment, each wheel measures 10″×24″ in diameter. Theleft and right wheels 64, 66 are connected by a steering tie rod 190shown in FIG. 4 which ensures that the wheels pivot in the same way atthe same time. It is connected at each end to the tie rod arm 78 of therespective wheel by means of a bolt with a nylon insert lock nut 192.

It will be understood that the hydraulic motor for each wheel unit isprovided with pressurized hydraulic fluid through hydraulic lines andfittings of standard construction which are readily available and wellknown in the art. Most of these lines are not shown for ease ofillustration. Some of these lines are indicated at 194 in FIG. 10.Connecting fittings for these lines can be supported by a small bracket196 shown in FIG. 12. It will be understood that the hydraulic motoritself and its gear box are of standard construction and accordingly adetailed description herein is deemed unnecessary.

Various other features in the illustrated exemplary low profile conveyorvehicle that are shown in FIGS. 1 to 3 include a plastic energy chain200 through which electrical cables and wires are fed for the operationof the vehicle and an energy chain guide 202 which helps to support themovement of the energy chain. Mounted to the frame on the left side isan electrical power box 204 of standard construction, this box having anaccess door 206. Mounted to the same side of the frame is an electricmotor 208 which powers first and second hydraulic pumps 210 and 212, thefirst pump 210 being used to drive the hydraulic motors for the wheelsand the second motor 212 being used to power other hydraulic componentson the vehicle. Two standard filters for the hydraulic system areprovided at 214 on the right side of the vehicle. Mounted above thesefilters is a junction box 116. A third hydraulic filter can be providedat 218 adjacent the pump 212. On or between the two longitudinal mainframes of the frame 16 and adjacent one of the cross-frames 220 is ahydraulic fluid reservoir 222. Another junction box for electricalcomponents including connectors is provided on the right side at 224.The side mounted electrical motor 38 for the head pulley is connectedtoga conveyor gear box 226 which has an output shaft connected to theshaft of the head pulley. In one embodiment, the motor 38 is a 7.5 kwattor 10 hp motor. Also on the right side of the vehicle there is mountedto the longitudinal frame member a hydraulic assembly manifold 230 whichis protected by a shroud or guard 232. On the same side of the framenear the motor 38 is a control box containing a programmable logiccontroller for controlling the operation and steering of the vehicle,the box indicated at 234. In a known manner, the vehicle 10 can also beprovided with water sprayers, two of which are indicated at 240, 242.Water hoses (not shown) are connected to the sprayers to reduce dustlevels generated by the conveyor system.

FIGS. 13 and 15 illustrate the pivot mechanism or pivoting hitchmechanism 44 for pivotably connecting the mobile conveyor machine ofFIGS. 1 and 2 at its inby end (also sometimes referred to herein as itsfirst end) to an adjacent end section of another mobile conveyor machinewhich can be constructed in the same manner as the machine or vehicle ofFIGS. 1 and 2. As indicated above, this pivot mechanism includes thecurved track 46 which can be of uniform transverse cross-section and, inan exemplary version, has the cross-section illustrated in FIG. 14. Thecurved track is bent in a horizontal circular arc as clearly shown inFIG. 5, for example, and this arc has a center of curvature locatedmidway between the propelling devices, that is the wheels 64, 66. Thiscenter of curvature is indicated at C in FIG. 3. The center of curvatureis on a common axis of rotation for the two wheels when these two wheelsare positioned to move the conveyor mechanism in a straightforwardsdirection. This axis of rotation is indicated at A in FIG. 3. The trackis rigidly mounted on the supporting frame 16 which includes a curvedbumper frame 350 having a rectangular transverse cross-section, thisframe extending the length of the track. The track, which is preferablymade of machined solid steel, can be welded to the bumper frame. Eachend of the track can be fitted with a rectangular stop plate 35Z securedin place by screws threaded into holes formed in each end of the track.An exemplary form of the track has a cross-section such as that shown inFIG. 14. The track has two opposite roller engaging sides 354, 356, withthe side 354 being on the inner side of the track and forming a concavecurve and the side 356 being on the outer side and forming a convexcurve. Each of these sides in the exemplary illustrated version engagesthree rollers with one of the rollers engaging the side 356 being shownin cross-section at 358 in FIG. 13. Another roller 360 is shown in partin FIG. 13 and this is one of the three rollers engaging the side 354.The three rollers engaging the side 356 form a first set of rollers andthe three rollers engaging the side 354 form a second set of rollers. Itwill be seen that the track 46 is captured and held between the firstand second set of rollers. The rollers of both sets have V-grooves 362formed about their circumferences. The use of three rollers in each sethelps keep the hitch unit correctly oriented on the track at all times.

Turning now to the exemplary cross-section illustrated in FIG. 14, theouter convex side 356 which faces towards an adjacent end of the mobileconveyor machine has an upper sloping surface 364 which extends at a 45°angle to the vertical centerline Z of the track. The outer surface alsohas a lower sloping surface 366 which extends at a 45° angle to the axisZ and there can be a short vertical surface provided at 368. The innerroller engaging side 354 is similarly shaped with 45° sloping surfacesat 370 and 371. These surfaces can be formed by a standard machiningprocess. Also formed in the track member is a rectangular groove 372which can extend the length of the track member on the side 356. Thepurpose of this groove is to accommodate a length of roller chain 374used in conjunction with an angle sensor described hereinafter.

Turning now to the construction of a roller mounting support body 376illustrated in FIGS. 17 to 19, this body is used to rotatably supportthe aforementioned two sets of rollers which engage the track 46. Thisbody includes a horizontally extending support plate 378 which can havea generally trapezoidal shape and is formed with six circular holes 380which accommodate upwardly extending shafts 381 of the rollers. Ifdesired, a shallow circular recess 382 can be formed around each hole topartially accommodate a nut 382 which is shown in FIG. 13 and threadedonto the roller shaft by suitable threads (not illustrated). Each rollerunit is a standard roller and therefore has not been shown in detail.The support body also has a vertical pivot pin support plate 384 whichis fixedly connected to an edge of the roller support plate 378. The twoplates can be welded together at 386. The horizontally extending,central pivot pin 56 is mounted in a circular hole formed centrally inthe support plate 384. The pin 56 is formed with a circumferentialflange 388 near its inner end, this flange resting against the supportplate 384. The inner end of the pivot pin can be welded to the plate384. To strengthen the support body 376 two rectangular side plates canbe welded thereto at 390, 392. A support plate 394 can be welded to thetop edge of the plate 384 and is shaped to form an obtuse angle. Fourfastener holes 396 can be formed in the outer end of this support plate.The arm 394 is used to detachably connect one end of the aforementionedenergy chain 200. If desired, a cover plate 395 (see FIG. 26) can beattached to the bottom of the support body 376 by means of screws 400inserted through the cover plate and threaded into holes 402. It will beunderstood that each roller is provided with internal bearings (notshown) of standard construction which allow the roller to rotate freelyabout its shaft.

Turning now to the construction of the pivoting hitch mechanism or hitchframe 44 illustrated separately in FIGS. 20 to 22, this frame ispivotably connected to the support body 376 by means of the pivot pin56. The pivot pin extends into a pin passageway which is formed in atransverse center of the frame. It will be understood that thepassageway 404 which has a circular cross-section, extends in a radialdirection relative to the radius of the track 46. The hitch frameincludes a central block 406 in which the passageway is formed, twotubular arm sections 408, 410 and two end sections 412, 414 located onopposite sides of the pivot pin and spaced therefrom, these end sectionsbeing adapted for a pivot connection to an adjacent end section of asecond or another mobile machine (similar to or the same as theillustrated machine of FIGS. 1 and 2) during use of the hitch apparatus.Each arm section 408, 410 can be formed from a horizontal top plate 416,a similar, horizontal bottom plate 418, an inner rectangular plate 420and a rectangular, vertical outer plate 422 (see FIG. 5). These platescan be made of ¾ inch steel plate and can be rigidly connected bywelding. Each end section 412, 414 can be formed from a bent steel plateforming an obtuse angle as shown in FIG. 20. The plate used can be oneinch steel plate and its connection to its arm section can bestrengthened by a triangular brace, or gusset 424. A circular hole 426is formed in the rounded end of each end section to receive a respectiveone of the car hitch pins 56 shown in FIGS. 1, 2 and 5. Thus, the hitchapparatus of this invention can be pivotably connected to an adjacentsecond mobile machine by means of these hitch pins which permit relativepivotable movement about a horizontal axis between the two mobilemachines or mobile conveyors.

As shown in FIGS. 13 and 22, a grease passageway 430 can be formed inthe top of the block 406 and a grease fitting or grease zerk is mountedin the block at the outer end of this passageway. Extending around thepivot pin are fiberglass bushings 432 with one located adjacent theflange 388 and the other located adjacent the outer end of pinpassageway 404. Also, a fiberglass thrust bearing 434 can be sandwichedbetween the inner end of the block 406 in a shallow, circular recess 435and the flange 388. Hitch mechanism 44 is retained on the central pivotpin 56 by means of a donut-shaped retainer plate 436 which can be ⅞^(th)inch plate having a central hole measuring 1 13/16^(th) inch. Both theplate 436 and the pivot pin are formed with aligned holes to receive adowel pin 438 which acts to prevent rotation of the plate relative tothe pin. The plate 436 is held in place by 3½ inch long screw 440 whichextends into a threaded hole formed in the center of the pivot pin. Itwill thus be seen that the hitch mechanism 44 is free to pivot about thehorizontal pivot axis formed by the pivot pin thereby allowing relativemovement about this pivot axis between the adjacent connected mobileconveyor vehicles.

For use with an automatic steering system for a train of these mobileconveyor machines of the type described above, it can be desirable forthe steering system to know the intercar angle between adjacent cars inthe train. Due to the fact that the present mobile conveyor machine hasno pivot joint located at the pivot axis between adjacent cars (in otherwords, there is only a virtual pivot point midway between the two wheelsof the machine described herein), a special intercar angle sensor can beprovided in conjunction with the pivot mechanism of the presentinvention so that an electrical signal indicative of the intercar anglecan be provided to the steering control for the conveyor train. Anexemplary form of such a sensor is illustrated in FIGS. 15, 16 and 23 to25. This sensor indicated generally by reference 450 is able todetermine the angle between the central longitudinal axis of theillustrated mobile conveyor machine 10 and a central longitudinal axisof another mobile conveyor machine which can be constructed in the sameor a similar manner as the illustrated machine. Although not shown inFIG. 23, the sensor includes the aforementioned tensioned roller chain374 mounted on the track 46. It will be appreciated that this chainforms a series of sprocket engaging recesses formed along one side ofthe track for at least most of the length of the track. These recessesare formed by recess forming members (ie. the pins of the chain). Therecesses could also be formed by machining them into the track memberitself. The other major component of the sensor is a rotational positiontransducer 452 which is mounted on the hitch mechanism 44 and, inparticular, on the roller support body 376. The sensor has a sensingsprocket 454 which drives an instrument to measure the intercar angle.The transducer 452 can, in one embodiment, send a signal to a Siemensprogrammable logic controller (PLC) used to steer the train of vehicles.This transducer, which can be of standard construction, can have asignal output ranging between 4-20 milliamps with the output dependingupon the sensed intercar angle.

With reference to FIGS. 24 and 25, in addition to the transducer, thereis shown a mounting arm 456 which includes an annular end section 458 onwhich the transducer can be mounted. The arm 456 is attached by a pivotpin 457 to the bottom edge of the side plate 392, this pivot pinextending through hole 458. There can be mounted in this hole two Oilitefriction bearings 460, one at each end. Rotatably mounting the shaft forthe sprocket 454 are two deep groove ball bearings 462 arranged next toone another. The bearings can be held in an opening by means of aretaining ring 464. On the transducer side of the bearings there can bea further external retaining ring 466. Welded to the arm on the sideopposite the sprocket is a transducer mount 468 which extends through anarc of more than 270°. Attached to this mount by four screws 470 is atransducer mounting plate 472. The central shaft of the transducerextends through this plate and is received within a central passagewayformed in sprocket shaft 474 and is secured thereto (for example by aset screw) for rotation therewith. The transducer is detachably mountedto the plate 472 by four screws 476. The end of an electrical controlcable operatively connected to the transducer is indicated at 478.

It will be seen from the above description that the transducer and itsmounting are pivotably mounted to the plate 392 of the hitch mechanism.An elongate coil spring 480 (see FIG. 15) is then provided to bias thesensor and in particular its sprocket 454 into engagement with theroller chain 374. The reason for this spring mounting is to provide someflexibility to the sensor mount, thereby reducing the possibility ofdamage, for example, if something such as dirt or a stone should becomelodged in the sprocket or the roller chain. It should also be noted thatthe roller chain is kept under tension itself by means of an adjustabletension rod 482 at one or both ends of the chain.

FIGS. 27 and 28 illustrate an actual connection between the inby end ofone mobile conveyor machine constructed according to the invention withthe outby end of another mobile machine 500, only an end section ofwhich is shown. Two car hitch pins 54 are used to attach the rollinghitch device 48 to the two ends of the frame 16. Each hitch pin can beheld in place by a washer plate 502 and a screw 504 that extends throughthe plate 502 and into a threaded hole in the end of the hitch pin.

Turning now to the mounting mechanism for the tail pulley 32, thismounting system as seen most clearly in FIG. 26 includes two parallellinks or swing arms 330 and 332 which are pivotably mounted on pivot pinsleeves 334 fixedly mounted on the inside of the frame 16. The innerends of the links are located along the longitudinal centerline of thecar and are pivotably connected to central mounting frame 336 whichprovides support fore a substantially vertically extending pivot pin338. Pivotably connected to this pin is a belt control arm 240 which inturn is pivotably connected to the actuator rod of a belt traininghydraulic cylinder 242. The closed end of this cylinder is pivotablyconnected to an adjustable horizontal support plate 244.

The tail pulley itself comprises two rotatable pulley sections 246 and248 which rotate about a non-rotating central support shaft (not shown)located along the centerline of the pulley indicated at 250. The shaftextends from opposite sides of a central, circular support block 252rigidly connected to one end of the control arm 240. Mounted on oppositesides of the support block are two central bearings located at 254, eachrotatably supporting a respective one of the pulley sections 246, 248.In a known manner, the exterior of these pulley sections comprises aseries of parallel, spaced-apart metal slats, the inner ends of whichare mounted on an outer annular support member which contains thecentral bearing. An outer bearing located at 256 is mounted on the outerend of each section of the shaft 50 to support the outer end of therespective pulley section. Horizontally extending frame members 260, 262are fixedly connected to the central frame 336 and are also connected tothe plate 244. These frame members are used to apply force to the tailpulley in order to tension same.

The position of the tail pulley can be adjusted for belt trainingpurposes using the hydraulic cylinder 242. In order to provide anautomatic system for correcting the position of the conveyor belt, aphotosensor system can be provided at each end of the tail pulley. Asillustrated, there are two photoemitters 266 mounted on the curved track46. For each of these photoemitters there is a photoreceiver 268 whichcan be seen in FIG. 26. As long as the conveyor belt is properlycentered on the tail pulley, pulses of a light beam can travel from eachphotoemitter 266 (through the gaps in the adjacent pulley section) toits respective photoreceiver which is mounted on the inside of one ofthe longitudinal frame members forming, the frame 16. However, if thebelt moves transversely on the tail pulley so as to block entirely oneof the light beams, this provides a signal to a programmable logiccontroller which causes retraction or extension of the actuator rod ofthe hydraulic cylinder 242. The actuator rod will move in a direction soas to cause the central shaft of the tail pulley to be pivoted in ahorizontal plane so as to tighten the belt on the side to which the belthas moved. This will tend to cause the belt to move back towards itscenter position.

As illustrated, each photosensor is aligned with the end section of thetail pulley so that the light beam is regularly broken by the parallelslats on the exterior of the tail pulley. Because of this arrangement,each photoreceiver sends a pulse signal to the programmable logiccontroller when the belt is not entirely blocking the light beam. Thus,if the belt is properly centered, pulse signals are being sent to thecontroller by both photoreceivers 268. When a pulse signal is not beingemitted by one of the light receivers, then this indicates that the belthas moved too much in the direction of this particular receiver and thecontrol system will take steps to re-center the belt.

Extending from a small winch 270 is a two inch wide nylon strap 272. Thewinch and strap are positioned above one photoreceiver 268 and aremounted on the inside of the main frame 16 of the vehicle. The strapextends to a metal hook which extends through a hole formed in the endof a vertical connecting plate 276. The plate 276 is rigidly connectedto one edge of the horizontal plate 244. It will be appreciated thatonce the conveyor belt is mounted in place and extends around the tailpulley (as well as the head pulley) the conveyor belt can be tensionedproperly by pulling on the strap 272 which in turn will cause the framemembers 260, 262 and the attached central frame 336 to move in adirection towards the tail pulley end of the vehicle.

While, the present invention has been illustrated and described asembodied in an exemplary embodiment, ie. an embodiment havingparticularly utility for use as a low profile, mobile conveyor vehiclesuitable for use with other similar conveyor vehicles, it is to beunderstood that the present invention is not limited to the detailsshown herein, since it will be understood that various omissions,modifications, substitutions and changes in the forms and details of thedisclosed conveyor vehicle and its method of operation may be made bythose skilled in the art without departing in any way from the spiritand scope of the present invention. For example, those of ordinary skillin the conveyor art will readily adapt the present disclosure forvarious other conveyor applications without departing from the spiritand scope of the present invention.

1. A mobile conveyor machine for a cascading conveyer system in the formof a series of mobile conveyor machines pivotally connected together inthe form of a conveyor train, said conveyor machine comprising: anelongate main supporting frame arranged substantially horizontally andhaving longitudinal side frame members and first and second ends, saidsupporting frame straddling a central longitudinal axis of the conveyormachine; a conveyor belt system mounted on said supporting frame andarranged to convey materials from said first end towards said secondend; a pair of transversely aligned propelling devices each separatelyconnected to said supporting frame for pivotal movement about agenerally vertical pivot axis, said pair being located near but spacedfrom said first end and having a common axis of rotation when saidpropelling devices are positioned to move the conveyor machine in astraight forwards direction, power steering means for steering said,pair of propelling devices; and a pivot mechanism for pivotablyconnecting said mobile conveyor machine at said first end to an adjacentend section of another mobile conveyor machine, said pivot mechanismincluding a curved track bent in a horizontal circular arc having acentre of curvature located midway between the propelling devices onsaid axis of rotation and rigidly mounted on said supporting frame and ahitch unit mounted for rolling movement on said track and connected tosaid track, said hitch unit having roller means for engaging said trackand said hitch unit being adapted for detachable connection to saidanother mobile conveyor machine.
 2. A mobile conveyor machine accordingto claim 1 wherein said track has two opposite roller engaging sides andsaid roller means includes a first set of rollers engaging one of saidroller engaging side and a second set of rollers engaging the otherroller engaging side, whereby said track is captured between the firstand second sets of rollers.
 3. A mobile conveyor machine according toclaim 1 wherein said hitch unit includes a pivot pin having a centralpivot axis, a roller mounting frame on which said roller means arerotatably mounted and to which said pivot pin is connected, and aconnecting frame mounted on said pivot pin for pivotal movement aboutsaid pivot axis which extends radially relative to said curved track,said connecting frame extending outwardly from opposite sides of saidpivot pin and having two opposite end sections adapted for connection tosaid adjacent end section of said another mobile conveyor machine,whereby said hitch unit enables the conveyor machine to pivot about saidcentral longitudinal axis relative to said another mobile conveyormachine.
 4. A mobile conveyor machine according to claim 3 wherein eachend section of said connecting frame has a pivot pin connector with acentral pivot axis substantially axially aligned with the pivot axis ofthe other pivot pin connector and the two pivot pin connectors enablesaid mobile conveyor machine to pivot about a substantially horizontalaxis relative to said another mobile conveyor machine.
 5. A mobileconveyor machine according to claim 1 wherein said pivot mechanismincludes sensor means for determining an angle between the centrallongitudinal axis of the mobile conveyor machine and a centrallongitudinal axis of said another mobile conveyor machine and fortransmitting an electrical signal indicative of said angle to a steeringcontroller for said conveyor train.
 6. A mobile conveyor machineaccording claim 1 including a tensioned roller chain extending alongsaid curved track, a rotational position transducer mounted on saidhitch unit, and a sensing sprocket rotatably mounted on a shaft of saidrotational position transducer and engaging said roller chain, whereinsaid transducer is capable of determining an angle between said centrallongitudinal axis of said mobile conveyor machine and a centrallongitudinal axis of said another mobile conveyor machine.
 7. A mobileconveyor machine according to claim 1 including a hydraulic motor meansfor driving each propelling device, hydraulic pump means for providinghydraulic fluid under pressure to said motor means, and an electricalmotor for powering said hydraulic pump means, said electrical motorbeing mounted on said supporting frame.
 8. A mobile conveyor machine foruse with an endless conveyor belt and a conveyor system in the form of aplurality of mobile conveyor machines pivotally connected together in anend-to-end manner, said conveyor machine comprising: a conveyormechanism having an elongate supporting frame with two longitudinal sideframe members on opposite sides thereof and two opposite end sectionsbetween which said conveyor belt extends when mounted on said conveyormechanism; a pair of transversely aligned wheel units for supporting andmoving said conveyor machine, each wheel unit having a wheel supportstructure connected to a respective one of said side frame members and awheel mounted on said wheel support structure for pivotable movementabout a respective substantially vertical pivot axis for steering theconveyor machine; a curved track mounted at one end of said supportingframe and extending in a substantially horizontal circular arc when saidconveyor machine is positioned on a horizontal surface, said arc havinga centre of curvature located between the wheel units; a hitch unitmounted on said track for rolling movement along said track and adaptedto connect pivotably said conveyor machine at said one end to anadjacent end section of another mobile conveyor machine; and sensormeans for determining a substantially horizontal angle between a centrallongitudinal axis of the conveyor machine and a central longitudinal ofsaid another mobile conveyor machine and transmitting an electricalsignal indicative of said angle to a steering controller of the conveyorsystem, wherein said conveyor machine during use as part of saidconveyor system is able to pivot about a substantially vertical axisextending through said centre of curvature relative to said anothermobile conveyor machine connected to the first mentioned conveyormachine by means of said hitch unit.
 9. A mobile conveyor machineaccording to claim 8 wherein said hitch unit includes a car hitch frameand rollers each rotatably mounted in said hitch frame for rotationabout a substantially vertical axis and for rolling engagement with saidtrack.
 10. A mobile conveyor machine according to claim 9 wherein saidtrack has two opposite roller engaging sides and said rollers include afirst set of rollers engaging one of said roller engaging sides and asecond set of rollers engaging the other roller engaging sides andwherein said track is captured and held between the first and secondsets of rollers.
 11. A mobile conveyor machine according to claim 8wherein said centre of curvature is located midway between the twowheels of said pair and along a common axis of rotation of the twowheels when said wheels are positioned to move the conveyor machine in astraight forwards direction.
 12. A mobile conveyor machine according toclaim 8 wherein each wheel unit includes a hydraulic motor for drivingthe wheel of the respective wheel unit and a planetary gear boxoperatively connected to said hydraulic motor and the wheel, saidhydraulic motor and gear box being part of said wheel support structureand being mounted for pivotal movement with their respective wheel. 13.A mobile conveyor machine according to claim 8 wherein said sensor meansincludes a series of sprocket engaging recesses formed along one side ofsaid track by recess forming members provided on the track.
 14. A mobileconveyor machine according to claim 13 wherein said sensor meansincludes a rotation position transducer mounted on said hitch unit and asensing sprocket rotatably mounted on a shaft of said transducer andengaging a small set of said recess forming members during use of theconveyor machine and wherein said transducer is capable of determiningsaid substantially horizontal angle and transmitting said electricalsignal.
 15. A hitching apparatus for use on a first mobile machine to beused with a second mobile machine connected to the first mobile machine,said apparatus comprising: a track member adapted for mounting at an endof the first mobile machine, said track member providing a track havingtwo substantially V-shaped, opposite sides and bent to form a circulararc having a centre of curvature, said sides including an outer convexside adapted to face towards the end of the first mobile machine and aninner concave side; and a hitch unit mounted for rolling movement onsaid track and adapted to connect pivotably said end of said firstmobile machine to said second mobile machine, said hitch unit includingrollers for engaging both of said opposite sides whereby the track iscaptured by said rollers said rollers having first and second sets ofrollers having V-grooves formed about their circumferences, said firstset engaging said outer convex side and said second set engaging saidinner concave side, wherein when said first mobile machine has thehitching apparatus mounted thereon, said first mobile machine is able topivot about a substantially vertical axis extending through said centreof curvature relative to said second mobile machine which is connectedthereto by said hitch apparatus.
 16. A hitching apparatus according toclaim 15 wherein said hitch unit includes a roller mounting support bodyin which said rollers are rotatably mounted and a pivoting hitch framepivotably connected by a pivot pin to said roller mounting support body,said hitch frame having a pin passageway receiving said pivot pin formedat a transverse centre thereof and extending in a radial directionrelative to a radius of said track member, said hitch frame having twoend sections on opposite sides of said pivot pin adapted for a pivotconnection to an adjacent end section of the second mobile machineduring use of the hitch apparatus.
 17. A hitching apparatus according toclaim 15 including a sensor device for determining a substantiallyhorizontal angle between a central longitudinal axis of the first mobilemachine and a central longitudinal axis of the second mobile machine andfor transmitting an electrical signal indicative of said angle to asteering controller.
 18. A hitching apparatus according to claim 17wherein said sensor device includes a series of sprocket engagingrecesses formed along one side of said track member for at least most ofthe length of the track member by recess forming members, a rotationalposition transducer mount on the hitch unit, and a sensing sprocketrotatably mounted on a shaft of said transducer and engaging differentones of said recess forming members during use of the hitch apparatus.19. A hitching apparatus according to claim 16 wherein said support bodyincludes a roller support plate having two rows of holes formed thereinreceiving shafts of said rollers and a pivot pin support plate fixedlyconnected to an edge of said roller support plate and extendingperpendicular thereto, said pivot pin being mounted centrally on saidpivot pin support plate and projecting away from the roller supportplate, and wherein said two rows of holes each extend along a circulararc having the same centre of curvature as said track member.